Mach number is a measure of an object's speed relative to the speed of sound in a particular medium, such as air. Mach 3 refers to traveling at three times the speed of sound.
G-forces, on the other hand, are a measure of acceleration or the force experienced by an object due to gravity or other accelerating forces. It is not directly related to Mach number, which measures speed.
To calculate the g-forces experienced during a particular maneuver or acceleration, you would need additional information such as the rate of acceleration, duration, and specific characteristics of the aircraft or vehicle involved.
Therefore, it is not possible to determine how many g-forces make up Mach 3 without further context or information.